/Engine/Plugins/Runtime/GeometryProcessing/Source/DynamicMesh/Public/Sampling/MeshBakerCommon.h
Compute interpolated tangent values inside triangle using barycentric coordinates
true if valid tangents were returned, false otherwise
bool TriBaryInterpolateTangents ( const void * Mesh, const int32 TriId, const FVector3d & BaryCoords, FVector3d & TangentX, FVector3d & TangentY ) const